METHOD FOR OPERATING AN ENGINE ARRANGEMENT
A method is provided for operating an internal combustion engine having at least one cylinder, said engine operating according to a four stokes cycle. The engine includes at least one controlled intake port to control communication of the combustion chamber with an intake line. The intake port is controlled to achieve a main open phase mainly during the intake stroke. The intake port is controlled to achieve an auxiliary open phase during the power stroke in view of heating the engine at cold start.
1 . Method for operating an internal combustion engine having at least one cylinder in which a piston connected to a crankshaft is displaced between a top dead center position and a bottom dead center position, thereby defining in the cylinder a variable volume combustion chamber, the engine operating according to a four stokes cycle including an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, wherein the engine comprises at least one controlled intake port and at least one controlled exhaust port to control communication of the combustion chamber respectively with an intake line and with an exhaust line, comprising
controlling the intake port to achieve a main open phase mainly during the intake stroke,
controlling the exhaust port to achieve a main open phase mainly during the exhaust stroke, and
controlling the intake port to achieve an auxiliary open phase during the power stroke.
2 . Method according to claim 1 , wherein the auxiliary open phase starts and ends during the power stroke.
3 . Method according to claim 1 , wherein the auxiliary open phase starts. between 30 and 70 degrees of crankshaft revolution after the top dead center position initiating the power stroke.
4 . Method according to claim 1 , wherein the auxiliary open phase ends between 50 and 120 degrees of crankshaft revolution after the top dead center position initiating the power stroke.
5 . Method according to claim 1 , wherein the auxiliary open phase lasts between 15 and 50 degrees of crankshaft revolution.
6 . Method according to claim 1 , wherein the engine is a compression ignition engine.
7 . Method according to claim 1 , wherein the intake port is controlled through an intake valve
8 . Method according to claim 1 , wherein the intake valve is controlled through a variable valve control system.
9 . Method according to claim 1 , wherein the routine of controlling the intake port to achieve an auxiliary open phase during the power stroke is performed in view of heating up the engine arrangement.
10 . Method according to claim 1 , wherein the routine of controlling the intake port to achieve an auxiliary open phase during the power stroke is performed in view of heating the engine at cold start.
11 . Method according to claim 1 , wherein the routine of controlling the intake port to achieve an auxiliary open phase during the power stroke is performed in view of heating up an exhaust after-treatment system.
12 . Method according to claim 1 , wherein the routine of controlling the intake port to achieve an auxiliary open phase during the power stroke is performed at low engine loads.
13 . Method according to claim 1 , wherein the engine is a multi-cylinder engine, in that the intake line comprise an intake manifold having at least one distinct intake duct per cylinder so that, during the routine of controlling the intake port to achieve an auxiliary open phase during the power stroke for one cylinder, post combustion gases are expelled through the intake port into the corresponding intake duct of the cylinder.